Ice making apparatus



D. E. M LEOD Feb. 13, 1962 ICE MAKING APPARATUS 2 Sheets-Sheet 1 Filed Sept. 12, 1957 FIGJ INVENTOR. DAVID EARLE Mac LEOD BY M M ATTOR N EY Feb. 13, 1962 MaCLEOD 3,020,726

ICE MAKING APPARATUS Filed Sept. 12, 1957 2 Sheets-Sheet 2 GEAR MOTOR SOLENOID FIG 2 COMPRESSOR INVENTOR. DAVID EARLE M LEOD Mfg ATTO R NEY United States Patent O F 3,020,726 ICE MAKING APPARATUS David Earle MacLeod, Syracuse, N. Y., assignor to Carrier Corporation, Syracuse, N.Y., a corporation of Delaware Filed Sept. 12, 1957, Ser. No. 683,599 2 Claims. (Cl. 62-138) This invention relates to automatic ice-making machines and more particularly to an improved control for initiating the ice harvesting cycle thereof.

There are ice making machines known having controls which initiate harvesting of the ice machine in response to the accumulation of ice in the ice making cells. A machine of this type is disclosed in my previous United States Patent No. 2,775,098, granted December 25, 195 6, and assigned to the assignee of the present invention. In this type of prior art machine, water to be frozen is supplied to the top of the ice making cells and drained from the bottom thereof. As ice is formed in these cells, it restricts the flow of water therethrough so that the water backs up and overflows from the top of the cells. This overflowing water is conducted to a control which initiates a harvesting cycle. The accuracy of the above type of control is dependent to a great extent on the rate at which water is supplied to the top of the cells and the rate at which this water drains through these cells. More specifically, there is the possibility that harvesting could be prematurely initiated if too much water is being supplied so that it overflows from the tops of these cells before the ice is fully formed therein. On the other hand, there is always the possibility that harvesting could be initiated after the optimum freezing time has elapsed if the water is being supplied very slowly and it continues to drain through the cells long after the ice has formed to the desired extent. It is with the overcoming of the foregoing shortcomings of the prior art that the present invention is concerned.

One object of the present invention is to provide a control which positively initiates an ice harvesting opera tion of an ice making machine in response to the accumulation of ice in the ice forming chambers thereof and is not materially influenced by the rate at which water is supplied to the ice forming cells.

Another object of the present invention is to provide an ice making machine control which is simple in construction, efficient in operation and inexpensive to manufacture. Other objects and attendant advantages of the present invention will readily be perceived hereafter.

The present invention relates to an ice making machine and a control therefor and comprises an ice forming chamber means for refrigerating said chamber, a conduit for conveying water to said chamber, and means responsive to the increase in pressure of water in said conduit due to ice forming in said chamber to initiate an ice harvesting operation. The present invention will be more fully understood when the following portions of the specification are read in conjunction with the accompanying drawings wherein:

FIGURE 1 is a schematic representation of an ice making machine embodying the control of the present invention; and

FIGURE 2 is a schematic wiring diagram of the electrical circuit of my improved control.

In FIGURE 1 is shown an ice making machine having an ice making section which has a plurality of ice forming chambers 11 therein. Chambers 11 are generally of the configuration desired in an ice cube. A cover 12 is adapted to be sealed in contact with the periphery of section 10 as at 13 and 14.

A sump 15 is provided having a float valve 16 and float 17 therein. Float valve 16 is connected to a suita- 3,020,726 Patented Feb. 13, 1962 ble water conduit 18. As is well known in the art, float 17 will cause valve 16 to supply water to sump 15, as required.

A water inlet conduit 19 having a pump 20 therein has one end thereof communicating with the water in sump 15. The other end of conduit 19 is coupled to cover 12. A water outlet conduit 21 has one end thereof coupled to cover 12 of ice forming section 10 and the other end thereof adapted to drain into sump 15. During the time that ice is being formed in chambers 11, water will be supplied to all of said chambers 11 by pump 20 and conduit 19. The water will rise upwardly in chambers 11 and overflow through conduit 21 back into sump 15.

Connected with water inlet conduit 19 is one end of water backup tube 22. It is to be noted that the uppermost portion 23 of water backup tube 22 is higher than the highest point of outlet tube 21.

When pump 20 is first placed in operation, water will rise to the same level in both ice forming section 10 and in water overflow tube 22. Once water starts flowing from ice forming section 10 through water outlet tube 21, the water level in water backup tube 22 will drop so that there is little or no water therein if the bottom of tube 21 is below the bottom of tube 22. However, it has been found that if the outlet end of outlet tube 21 is terminated above the lower end of backup tube 22, then water will rise in the latter to the same level as the lower end of outlet tube 21.

As ice forms in ice forming section 10, especially in the narrowest portions 24 thereof, the flow of water through ice forming chamber 10 will be obstructed. This will cause pump 20 to produce an increased water pressure in water inlet conduit 19. The obstruction of section 10 will cause an increased pressure in conduit 19 and therefore cause water to rise in water backup conduit 22 until it flows from the other end thereof. The water flowing out of backup conduit 22 is adapted to strike a control such as a thermostatic bulb 25 located in well 26 which is in communication with tube 27 for leading this overflow water back to sump 15. As soon as bulb 25, which is connected by capilliary 28 to bellows 29 (which in turn controls switch 30), is actuated by water from tube 22, it will cause the initiation of a defrost cycle, as explained in detail hereafter. However, it must be noted that water will not fiow upwardly through backup tube 22 until the ice has formed to a desired extent in ice forming chamber 10. 'As noted above, the level to which water rises in the tube 22 prior to the formation of ice in chambers 11 is determined by the position of the lower end of Water outlet tube 21. Thus, by positioning the lower end of Water outlet tube 21, as desired, the head of water required to cause water to overflow from backup tube 22 may be adjusted to meet any particular situation. It is to be observed that harvesting is initiated in response to the restriction of ice forming in chamber 10 and is substantially independent of the rate at which Water is supplied to this ice forming section 10 by pump 20.

Ice forming section 10 is refrigerated by a conventional refrigeration system which includes compressor 31,.condenser 32, an expansion member such as capillary 33, and evaporator 34, which is in contact with ice forming section 10. A hot gas bypass line 35 having a solenoid actuated valve 36 therein couples the compressor discharge line directly to the evaporator 34 for harvesting the formed ice cubes, as explained hereafter.

The control circuit for the control of the present invention is disclosed in FIGURE 2. Compressor 31 is coupled through master switch 37 across leads L and L Also coupled across leads L and L through switch 30 and master switch 37 is a timer motor 38 (FIGURES 1 and 2). It can thus be seen that as soon as bulb 25 is affected by water flowing from backup tube 22, switch 30 will close to energize timer motor 38. Timer motor 38 is of the type which will operate for a predetermined time and which has a plurality of cams (not shown) mounted on a shaft, each of these cams being adapted to actuate switches 39, 40, 42, and 43 during its operation in the following manner: As soon as timer motor 38 is energized, switch 39 therein will close to maintain the timer motor energized regardless of whether switch 30 opens in response to fluctuations of conditions in the area of bulb 25. As soon as timer motor 38 begins operation, switch 40 therein will close to energize solenoid 41 of solenoid operated valve 36 to cause hot gas to be supplied directly to the evaporator 34 to start melting the ice free in ice forming section 10. Also as soon as timer motor 38 is energized, switch 42 will open to disrupt the flow of current to pump 20. After timer motor 38 has been in operation for a predetermined time which is suificient to permit the hot gas in evaporator 34 to loosen the ice in ice forming section 10, switch 43 is actuated to close a circuit to gear motor 44 (FIGURES 1 and 2) to cause the latter to pull cover 12 away from ice forming section 10.

Cover 12 may have sleeves such as 45 afiixed thereto which are adapted to slide on bars 46, which are rigidly affixed to the frame (not shown) of the machine. Gear motor 44 has arm 47 afiixed to the shaft thereof, this arm being pinned to link 48 at 49. The rotation of arm 47 will cause link 48 which is also connected to cover 12 at 50 to pull cover 12 away from ice forming section 10. Gear motor 44 is of the type which will make one 360 revolution and then stop. Thus, when arm 47 approaches a position which is 180 away from the position shown in the drawing, cover 12 will be in its fully opened position. Prior to the start of rotation of gear motor 44, sufficient heat will have been provided to the ice bodies in ice forming section so that they will be released therefrom, while still adhering to cover 12. As arm 47 approaches its 180 position from start-up, cover 12, which is flexible, is stretched by suitable pins (not shown) and the ice bodies are loosened therefrom whence they fall onto a slide 51 which conducts them to a suitable ice receiving receptacle 52. As link 47 continues it rotation to approach its position shown in FIGURE 1, cover 12 will then start closing. The rate of rotation of gear motor 44 is timed to permit complete release of ice bodies from cover 12.

To insure proper operation of the foregoing cycle, an interlock switch 53 is provided (FIGURES 1 and 2) which is adapted to close a circuit through solenoid 41 and gear motor 44 as soon as cover plate 12 is moved away from its closed position. It will thus be seen that, in the event that ice jams between cover plate 12 and ice forming section 10 before the former has reached its fully closed position and after timer motor 38 has stopped, solenoid 41 and gear motor 44- will remain energized to cause the ice to melt and cover 12 to close, respectively. It is not until cover 12 returns to its fully closed position that switch 53 will open to permit gear motor 44 and solenoid 41 to become de-energized. By the time that gear motor 44 returns cover 12 to its fully closed position, timer motor 38 will have stopped and contacts 39, 40, 42 and 43 therein will have returned to their solid line positions so that solenoid 41 is de-energized, pump 20 is energized, and gear motor 44 is de-energized so that the machine can start another ice making operation. It will also be noted that arms 4 and S4 of switch 53 assume a dotted line position when switch 53 is actuated by the closed cover 12. It is to be noted that all of the switches in FIGURE 2 assume their solid line positions during the ice-making cycle and will assume their dottedline position at various times during the ice-harvesting cycle, as explained in detail above.

It will thus be seen that I have disclosed a defrost control for an ice making machine which is simple in construction and positive and eflicient in operation. Furthermore, it will readily be seen that my present control overcomes the shortcomings of the prior art controls.

While I have described a preferred embodiment of my invention, I desire it to be understood that it may be otherwise embodied within the scope of the following claims.

I claim:

1. In an ice making machine, the combination of a plurality of ice forming chambers, cover means to seal the ice forming chambers, a sump, an inlet conduit for conveying water from the sump to said chambers, an outlet conduit for conveying water from the chambers to said sump, means for refrigerating the chambers to form ice therein, means for heating the chambers to harvest the formed ice, a water backup tube connected to the inlet conduit for conducting Water from the inlet conduit when the flow of water through the chambers is impeded by the formation of ice, a predetermined increase in pressure of water in the inlet conduit during ice formation causing water to flow through said backup tube, and means responsive to the flow of water through said backup tube to initiate ice harvesting and move the cover means away from the ice forming section.

2. In an ice making machine, the combination of an ice forming section containing a plurality of ice forming chambers therein, a cover member to seal the ice forming section, means for moving the cover member away from the ice forming section, a sump, an inlet conduit connected to the cover member for conveying water from the sump to said chambers, means for refrigerating the chambers to form ice therein, means for heating the chambers to release the formed ice, an outlet conduit connected to the cover member for carrying water from the chambers to the sump, a water backup tube attached to the inlet conduit, means for forwarding water from the sump through the inlet conduit, the chambers and the outlet conduit to the sump, said backup tube conducting water from the inlet conduit when flow of water through the chamber is impeded by the formation of ice, a predetermined increase in pressure of water in the inlet conduit during ice formation causing water to flow through said backup tube and means responsive to the flow of Water through said backup tube to initiate ice harvesting and move the cover member away from the ice forming section.

References Cited in the file of this patent UNITED STATES PATENTS 2,593,874 Grandia Apr. 22, 1952 2,633,005 Lauer Mar. 31, 1953 2,701,452 Hopkins Feb. 8, 1955 2,763,996 Lees Sept. 25, 1956 2,821,070 Watt Jan. 28, 1958 

